Kaveri River Water Flow

The Kaveri River, also spelt as Cauvery, is one of the major rivers of southern India and serves as a lifeline for the states of Karnataka, Tamil Nadu, Kerala, and the Union Territory of Puducherry. It originates in the Western Ghats and traverses a distance of over 800 kilometres, supporting agriculture, industry, and hydropower generation along its course. The river’s water flow—its volume, seasonal variation, and distribution—has immense significance for irrigation, ecology, and interstate relations.

Geographical Origin and Course

The Kaveri River originates at Talakaveri, located in the Brahmagiri Hills of the Coorg (Kodagu) district in Karnataka, at an elevation of about 1,341 metres above sea level. From its source, it flows eastward through Karnataka and Tamil Nadu, forming one of the most fertile river basins in the Indian peninsula before emptying into the Bay of Bengal.
The major course of the river can be divided into the following sections:

1. Upper Course (Karnataka Plateau): The river flows swiftly through rocky terrain and gorges, including the famous Shivanasamudra Falls, where the river splits into two channels that reunite downstream.
2. Middle Course (Mysore and Mandya regions): The flow here is regulated by major reservoirs such as Krishna Raja Sagar (KRS), supporting irrigation and hydroelectric projects.
3. Lower Course (Tamil Nadu Plains): As it enters Tamil Nadu, the river’s flow becomes slower and more distributary, feeding extensive canal networks before forming a delta near Tiruchirappalli and Thanjavur, known as the Rice Bowl of South India.

Tributaries and Drainage System

The Kaveri’s flow is sustained by numerous tributaries originating from both sides of the Western and Eastern Ghats. Major tributaries include:

• Left-bank tributaries: Harangi, Hemavati, Shimsha, Arkavathi
• Right-bank tributaries: Lakshmana Tirtha, Kabini, Suvarnavathi, Bhavani, Noyyal, and Amaravati

These tributaries enhance the Kaveri’s flow during the monsoon season, contributing to its perennial nature, though its discharge varies widely between wet and dry months.

Water Flow Characteristics

The average annual flow of the Kaveri River is estimated to be around 740 to 800 thousand million cubic feet (TMC ft), though it fluctuates significantly depending on rainfall patterns. The river is primarily rain-fed, with the South-West and North-East monsoons playing crucial roles in determining seasonal discharge.
Key characteristics of its flow include:

• Seasonal Variation: The river’s flow peaks between June and December, corresponding with the monsoon months. The lean season usually occurs from February to May, when water availability declines sharply.
• Regulated Flow: Several major dams—such as the Krishna Raja Sagar (Karnataka), Mettur (Tamil Nadu), and Kabini (Wayanad, Kerala)—control the river’s discharge for irrigation and power generation.
• Groundwater Interaction: The river also contributes to groundwater recharge in the basin areas, sustaining agricultural activities even during dry months.

Major Dams and Irrigation Projects

The Kaveri basin is heavily developed for irrigation, supporting millions of hectares of farmland. The most significant water control structures include:

• Krishna Raja Sagar (KRS) Dam: Constructed across the Kaveri in Mandya district, Karnataka, it provides water for irrigation, drinking purposes, and power generation.
• Mettur Dam: Built in Tamil Nadu across the Kaveri at Salem district, forming the Stanley Reservoir, it regulates flow to the delta region and supports extensive agricultural activities.
• Kabini and Harangi Dams: Key tributary reservoirs contributing to Kaveri’s regulated discharge.
• Upper and Lower Anicut Dams: Located in Tamil Nadu, these structures distribute water through an intricate canal network feeding the fertile delta plains.

These projects collectively enable the Kaveri basin to produce multiple crops annually, including rice, sugarcane, banana, and turmeric.

Hydrological and Climatic Influences

The river’s flow is closely linked to monsoon rainfall in the Western Ghats. Years of weak monsoon or delayed rainfall lead to reduced inflow into the reservoirs, triggering water shortages downstream. Conversely, heavy rainfall may result in flooding, particularly in the low-lying delta regions.
Long-term data indicate that climate variability has increasingly influenced the Kaveri’s discharge patterns. Deforestation, urbanisation, and changing land-use patterns in the upper catchment areas have also affected natural runoff and sediment load.

Interstate Water Distribution and Disputes

The Kaveri River Water Dispute is one of the most well-known and long-standing water-sharing conflicts in India, involving Karnataka, Tamil Nadu, Kerala, and Puducherry.
The dispute centres on the allocation of the river’s annual flow and reservoir releases, particularly during periods of drought. The historical context includes:

• 1892 and 1924 Agreements: Between the princely state of Mysore (now Karnataka) and the Madras Presidency (now Tamil Nadu), governing water use and irrigation development.
• Post-Independence Period: Growing demand from both states led to disputes over equitable sharing, especially as Karnataka expanded its irrigation projects.
• Cauvery Water Disputes Tribunal (CWDT): Established in 1990 by the Government of India, the Tribunal issued its final award in 2007, allocating water among the riparian states based on hydrological and crop data.
• Supreme Court Verdict (2018): Revised allocations slightly, granting Karnataka 284.75 TMC ft, Tamil Nadu 404.25 TMC ft, Kerala 30 TMC ft, and Puducherry 7 TMC ft, with 10 TMC ft reserved for environmental and system losses.

A Cauvery Water Management Authority (CWMA) now monitors the implementation of this sharing arrangement, regulating reservoir releases and ensuring compliance during drought and flood periods.

Environmental and Ecological Significance

The Kaveri basin supports rich biodiversity, including forests, wetlands, and estuarine ecosystems. Its flow sustains wildlife sanctuaries such as the Ranganathittu Bird Sanctuary and Cauvery Wildlife Sanctuary. The river’s delta region, with its network of distributaries and backwaters, supports extensive fisheries and mangrove vegetation.
However, excessive damming, sand mining, pollution from urban waste, and agricultural runoff have degraded water quality and reduced flow in several stretches. Sustainable management practices, including afforestation and regulation of industrial discharge, are essential to maintain ecological balance.

Water Flow Monitoring and Management

The Central Water Commission (CWC) and state irrigation departments continuously monitor the river’s flow using hydrological gauges, rainfall data, and satellite-based observation systems. Regular assessments help predict drought and flood events and guide reservoir management.
Modern initiatives include:

• Real-time data sharing between riparian states.
• Remote sensing technologies for monitoring catchment rainfall and inflow.
• Integrated water resource management (IWRM) projects to optimise use across sectors.